Medium
7 03 on Ariston Microsystem 15

Your boiler is having trouble communicating with one of its internal temperature sensors, which may cause your heating or hot water to work inconsistently.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Zone 3 outgoing sensor defective

From this model's manual
Verified against the Ariston E Combi One 24 installation & service manual, page 39.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

What causes this fault?

This fault occurs when the boiler is unable to read the temperature data from the specific sensor responsible for your third heating zone. The most common cause is a failure of the internal thermistor (NTC sensor) or a loose connection in the wiring harness that links the sensor to the main control board.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

7 01View →7 02View →

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